An optical receptacle is used as a component for optically connecting an optical fiber connector to an optical element such as a light receiving element, a light emitting element, etc., in an optical module of an optical communication transceiver (e.g., referring to Patent Document 1).
In recent years, it is necessary to increase the speed of optical communication transceivers as IP traffic increases. Generally, the configurations of the transceiver and the like that employ the receptacle-type optical module are standardized; and it is necessary to downsize the optical module because the space necessary for the electronic circuit increases as the modulation rate of the optical signal emitted from a semiconductor laser which is one optical element is increased.
As an optical receptacle for downsizing the optical module, a method such as that of Patent Document 2 is known in which a recess having a tubular configuration is provided in a portion of the ferrule and a lateral groove having a prescribed width is provided on the optical element side. In such a case, it is necessary to be in a state in which the optical fiber protrudes from the through-hole of the ferrule to easily perform processing of the optical fiber end portion; and there are problems of breaking when an external force is applied to the optical fiber, or of the coupling efficiency decreasing due to movement of the protruding portion of the optical fiber when using as an optical module.
Also, a method is known in which a large diameter portion is provided in the through-hole of the ferrule, and a resin that is transmissive is filled into the periphery of the fiber (e.g., referring to Patent Document 3). However, in such a case, when a temperature change occurs due to the different coefficients of thermal expansion of the optical fiber and the resin filled into the periphery of the optical fiber, there are problems of stress being applied to and breaking the optical fiber and the fiber tip undesirably moving. These problems occur particularly when the optical fiber is positioned toward the outer side from the center of the large diameter portion of the through-hole of the ferrule. Also, because processing of the end surface of the optical fiber is necessary, there is a problem of economic production being difficult.